Should I switch antidepressants?

It's a common myth that antidepressants are a ‘quick fix’ for mental health problems such as depression and anxiety. In reality, for many people non-drug treatments such as talking therapy offer better long term results. In addition, finding the right medication isn't an easy process and it can take time before the effects are felt. And not everyone will feel better with the first antidepressant they try.

When to consider changing antidepressants

For people living with mental illness, antidepressants can be an invaluable lifeline. However, it can be a case of trial and error to find the right type.

"There is a large body of evidence for the efficacy of antidepressant medication in those who experience moderate to severe depressive disorder," says Dr Natasha Bijlani, a consultant psychiatrist at Priory Hospital Roehampton.

"These drugs can have a valuable role to play in the management of moderate to severe anxiety disorders, alongside psychological interventions such as cognitive behaviour therapy," she adds. "The initial selection of an antidepressant is usually based on anticipated side effects, safety and tolerability for individual patients, patient preference, prior experience of antidepressant medication and cost."

As is the case with many medications, however, people can respond differently to antidepressants. Individuals may find one type of drug more effective than another, so it can be necessary to change medications over time until a good match is found.

"There can be various reasons for a doctor to consider switching to a different antidepressant," says Bijlani. "One reason could be if there is no response, or not a sufficient response or improvement with the first one after four to six weeks of use, even after the dose has been increased to the maximum recommended level for that drug."

According to a 2015 review, one in three people will be symptom-free after taking one antidepressant. Therefore, some people may require several antidepressant trials before an "effective symptom remission" can be achieved, Bijlani explains.

Side effects of antidepressants

People may also want to change antidepressants because of persistent side effects. Although they can be unpleasant, the initial side effects of antidepressants often subside after a few weeks. The common side effects of SSRIs (selective serotonin reuptake inhibitors) and SNRIs (serotonin-noradrenaline reuptake inhibitors) include feeling agitated or more anxious, feeling sick, indigestion, digestive problems, loss of appetite, insomnia and headaches.

Side effects of tricyclic antidepressants (TCAs) include dry mouth, slight blurring of vision, constipation, problems passing urine, drowsiness, dizziness, palpitations or a fast heartbeat (tachycardia).

After a few weeks, the side effects should ease as the body adjusts to the medicine. However, some side effects can persist, and changing medications may help.

"All medications have the potential to cause unwanted effects, in addition to the desirable effects for which the medication will have been prescribed in the first place. Side effects can vary from person to person and a drug that is very well tolerated and beneficial for one person may be completely unsuitable for another," explains Bijlani.

"Some patients may experience a slight increase in agitation or anxiety as their body adjusts to some of the effects of the medication. If any of these symptoms become more intense within seven to 10 days of starting treatment, then the individual should seek guidance from the doctor who prescribed the medication."

In rare cases, some patients may experience suicidal thoughts while taking antidepressant medication. "They should be advised to seek immediate and urgent medical help," says Bijlani.

"There are many different classes of antidepressants available and if one particular drug doesn't seem effective or leads to unpleasant side effects, your doctor is likely to be able to suggest alternatives that could be better tolerated and efficacious for your symptoms."

Why switching antidepressants is a careful process

It's crucial not to stop taking your medication without speaking to your doctor first. When switching medications, the process needs to be gradual and any increases in dosages should be slow. Stopping your current medication too quickly can lead to withdrawal symptoms or can cause symptoms of depression or anxiety to return.

It's also important that your doctor monitors you for side effects as you change medications, as well as for adverse interactions between different ones. "Switching antidepressants can sometimes lead to withdrawal symptoms, particularly if the change is carried out too quickly," says Bijlani.

"Although antidepressants are not considered to be addictive, suddenly discontinuing or reducing the dose by too much can lead to uncomfortable and sometimes very unpleasant discontinuation symptoms which include flu-like symptoms, insomnia, irritability, crying spells and agitation. Patients can also occasionally experience movement disorders and problems with memory and concentration."

Sometimes, if two antidepressants are taken at the same time as part of the switching process, people may experience problems such as low blood pressure and drowsiness.

Serotonin syndrome

Some people may experience a rare condition called serotonin syndrome. This occurs when too much serotonin - a neurotransmitter that plays an important role in the functioning of nerve and brain cells and mood regulation - builds up in the body.

"Mild symptoms of serotonin syndrome include insomnia, anxiety, nausea, diarrhoea, and increased heart rate," says Bijlani. "Patients can go on to develop moderate and severe symptoms such as agitation, tremor, flushing, low-grade fever and eventual confusion, higher fever, respiratory failure, and even death."

To reduce the risk of serotonin syndrome, cross-tapering is needed for some combinations of antidepressants. This involves gradually reducing the dose of the first antidepressant at the same time as slowly increasing the dose of another. For others, it may be safe to stop one antidepressant and start the other the next day.

To avoid problems, switching antidepressants should always be done under the supervision of your doctor, who can advise on doses and keep track of any side effects or problems.

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